Online pigging system and method

ABSTRACT

The disclosure provides a heat transfer system having a tubing coil for heating fluid flowing therein, where the tubing coil can be pigged (descaled) while operationally online, instead of offline. The online system uses an assembly of valves and associated equipment to connect to a pig launcher and pig receiver while the system is online. A valve opens and the pig launches into the flow stream under pressure through the valve and travels along the tube with the fluid. The system continues to produce heated fluid with the pig in the flow path. A pig receiver receives the pig after the pigging, and then is isolated from the flow path of the heated fluid by another valve. The pig launcher, pig receiver, and pig are removed, and this process is repeated for any other passes in the tubing coil.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosure relates generally to a method for cleaning heat transfersystems, and more specifically, to heat transfer systems having tubingcoils for passing fluid therethrough to be heated by a heat source.

2. Description of the Related Art

Heat transfer systems having tubing coils are used in a number ofapplications. A heat source transfers heat through a heat exchangergenerally having a chamber and a tubing coil therein. The heat sourceheats the tubing coil that in turn heats a fluid flowing through thetubing coil. The heat source can be, for example, a fuel combustionburner, radiant heat source, including infrared, hot fluids, includinggases, or exhaust fluids from a turbine or engine, or other waste heatfluids. FIG. 1 is a representative schematic diagram of a fire heaterfor heating hydrocarbon in a tubing coil. If the fluid is a hydrocarbon,the hydrocarbon in the tubing coil can be heated to change viscosity toimprove flowability and handling. The system 100 can include a heatsource, such as a burner 102, that provides heat into a chamber 104having a tubing coil 106. The tubing coil 106 has an inlet 108 and anoutlet 110 through which the hydrocarbon can flow in and out the tubingcoil. An exhaust 112 allows exhaust gases to exit the chamber 104. Ifthe temperature is sufficiently high, the hydrocarbon fluid can undergoa process known as “cracking,” when the high-boiling, high-molecularweight hydrocarbon fractions of a hydrocarbon fluid are converted intolighter weight, more valuable, hydrocarbon fluids, such as gasoline andother products.

If the fluid is water, the water can be heated, for example, into steam.An exemplary typical heat transfer system for water is a once-throughheat recovery steam generator (“OTHRSG”). FIG. 2 is a representativeschematic diagram of an OTHRSG system with a tubing coil. The OTHRSGsystem 200 uses a heat exchanger, having a chamber 204 with a tubingcoil 206. The system 200 can include a heat source 202, such as gasturbine exhaust or waste heat, to transfer heat into water passingthrough the tubing coil 206 from an inlet 208 to an outlet 210. Anexhaust 212 allows exhaust gases to exit the chamber 204. The resultingheated water, such as steam, be used in various processes, including todrive a steam turbine.

A specialized type of OTHRSG without boiler drums is known as aonce-through steam generator (“OTSG”). FIG. 3 is a representativeschematic diagram of an OTSG system. The OTSG system 300 includes achamber 304 with a tubing coil 306 therein. The system 300 can include aheat source 302, such as a burner, to transfer heat into water passingthrough the tubing coil 306 from an inlet 308 to an outlet 310. Anexhaust 312 allows exhaust gases to exit the chamber 304.

More specifically, OTSG systems can be used, for example, to generatesteam for oil sands for crude oil exploration, extraction, production,and related markets, including Steam Assisted Gravity Drainage (SAGD)projects. A representative OTSG system is shown in FIGS. 4 and 5 for usewith an oil sands production facility. FIG. 4 is a schematic perspectiveview of an OTSG facility for extraction of hydrocarbon from oil sands.FIG. 5 is a schematic cross sectional side view of the OTSG unitproducing steam for extraction of hydrocarbon from the oil sands. Thefigures will be described in conjunction with each other.

An OTSG system 2 includes water tanks 4 with OTSG units 8 located in abuilding 6. An OTSG unit 8 includes a heat source 10, such as a burner,that is used to generate heat inside a chamber 15 typically having afeedwater preheat zone 12 and a steam generation zone 14. A supply line13 provides feedwater to a tubing coil 16 through a tubing inlet 18.Heat is transferred from the heat source to the feedwater in the tubingcoil 16 to generate steam. The steam exits a tubing outlet 20 of thetubing coil 16 into a steam pipeline 22 that transports the steam intogeological strata 24 having an oil sands layer 26 and injects the steamthrough openings in the pipeline 22 in an injection zone 28. The processuses the steam heat to heat the hydrocarbons in the sand to a flowableconsistency for extraction by flowing by gravity the hydrocarbons in acollection zone 30 into a collection pipeline 32. The collectionpipeline flows the hydrocarbons into a processor unit 34 for extractionof the water from the hydrocarbons and other processing.

The tubing coil 16 of an OTSG unit typically has multiple tubing passesdesigned into its heat transfer system, and typically four or sixpasses. Each pass is a serpentine-arranged single tube with essentiallyone inlet 18, as a point of entry, and one outlet 20, as a point ofexit, per pass. In addition to heating by convection from hot gases, thetube is typically disposed along a radiant wall in the OTSG unit tomaximize heat transfer. For each tubing pass, feedwater enters the inlet18 for the tube and mostly steam with some water (typically 80% steamand 20% saturated water) exits through the outlet 20 of the tube.

However, feedwater impurities naturally build up in the tubing coil 16of the OTSG unit as the water is converted to steam. The impuritiescause scaling along the tube walls (known as “tube fouling”) whichreduces heat transfer effectiveness and may eventually lead to pluggingof the tube. Over time, scaling adversely impacts steam production andfuel consumption with subsequent impact on unit operation and thereforeoil production from the oil sands.

Most oil producers employing OTSG technology utilize multiple OTSG unitsmainly due to the scaling issue. The only currently available technologyfor descaling OTSG units is a process called “offline pigging.”

Offline pigging requires taking the entire OTSG unit offline from amulti-OTSG unit configuration. The individual OTSG unit 8 is shut downand steam production is halted for that one unit. As the individual OTSGunit is taken offline, equipment from other portions of the OTSG unitthat is connected to the inlet and outlet of the tubing coil, andparticularly the tubing pass, is disconnected and removed. A piggingsystem is mounted to the inlet and outlet of the tubing pass. Thepigging system includes a pig launcher, pig receiver, and a pig. The piglauncher is placed at the inlet of tubing pass and pig receiver isplaced at the outlet of tubing pass. The pig is launched from the piglauncher into the tubing pass under water pressure particular to theoffline pigging process. As the pig passes through the tubing pass, thepig removes scales from the tubing inside surfaces. The pig exits theoutlet and is received by the pig receiver. Flush water follows the pig,and scale is carried away with water out of the system. One pass ispigged at a time. For units with multiple passes, each pass is descaledin turn by disconnecting and removing the equipment from the inlet andoutlet of each pass, connecting a pigging system to the inlet andoutlet, launching and receiving the pig, and flushing out the scale,then reconnecting. Once all the passes have been descaled, the unit isthen turned back on for normal operation. This offline pigging practiceis the current industry convention.

The pigging process is repeated for each OTSG unit on a rotation basis.It normally takes a few hours for an OTSG unit to cool down fordescaling, and a few more hours to resume full capacity steam productiononce started up again to full operating temperatures. Further, when theOTSG unit is used for the oil sands, the production may be delayed forseveral days to even a month or more, while the production enveloperestabilizes the heat and pressures underground. Thus, often a duplicateOTSG unit is available to maintain the steam production, while the otherOTSG unit is offline for descaling. However, the additional OTSG unitavailable for use when the other unit is offline is an intensive capitalexpenditure with operating expenditures as well.

Further, the turning off and on of the OTSG unit in the descalingprocess has a measurable impact on useful life on the tube or tubes andrelated equipment due to thermal stresses from transient conditions,thereby increasing maintenance with labor and material replacement costsover the life of the system.

Thus, there remains a need for an improved system and method fordescaling an OTSG unit without having to force the OTSG unit offline.

BRIEF SUMMARY OF THE INVENTION

The disclosure provides a heat transfer system having a tubing coil forheating fluid flowing therein, where the tubing coil can be pigged(descaled) while operationally online, instead of offline. The onlinesystem uses an assembly of valves and associated equipment to connect toa pig launcher and pig receiver while the system is online. A valveopens and the pig launches into the flow stream under pressure throughthe valve and travels along the tube with the fluid. The systemcontinues to produce heated fluid with the pig in the flow path. A pigreceiver receives the pig after the pigging, and then is isolated fromthe flow path of the heated fluid by another valve. The pig launcher,pig receiver, and pig are removed, and this process is repeated for anyother passes in the tubing coil. In at least one embodiment, the heattransfer system can include a heat recovery steam generator system, suchas a once-through steam generator System (“OTSG”).

The disclosure provides a heat transfer system, comprising: a heatsource coupled to a chamber having a tubing coil disposed therein, theheat source adapted to heat at least a portion of a fluid in the tubingcoil into a heated fluid, the tubing coil having an inlet and an outlet,the inlet adapted to receive the fluid for flowing through a flow pathin the tubing coil and the outlet adapted to allow the heated fluid toexit the tubing coil; a first inlet connection coupled to the inlet forcoupling with a supply line to supply the fluid into the tubing coil; asecond inlet connection coupled to the inlet and fluidicly independentof the first inlet connection; an inlet valve coupled to the secondinlet connection; a third inlet connection coupled to the inlet valve; apig launcher coupled to the third inlet connection, the pig launcheradapted to launch a pig into the tubing coil through the inlet valve; afirst outlet connection coupled to the outlet and adapted to allow theheated fluid to exit therethrough; a second outlet connection coupled tothe outlet and fluidicly independent of the first outlet connection; anoutlet valve coupled to the second outlet connection; a third outletconnection coupled to the outlet valve; and a pig receiver coupled tothe third outlet connection, the pig receiver adapted to receive the pigfrom the tubing coil through the outlet valve. The heat transfer systemcan include a heat recovery steam generator, where the fluid in thetubing coil includes feedwater, and the heated fluid includes steam.

The disclosure also provides a method of pigging a heat transfer system,the system having a heat source coupled to a chamber having a tubingcoil disposed therein, the tubing coil having one or more tubing passes,the heat source adapted to heat at least a portion of a fluid in thetubing coil into a heated fluid, the tubing coil having an inlet and anoutlet, the inlet adapted to receive the fluid for flowing through aflow path in the tubing coil, and the outlet adapted to allow the heatedfluid to exit the tubing coil, the system further having: a first inletconnection coupled to the inlet for coupling with a supply line tosupply the fluid into the tubing coil; an inlet valve coupled to theinlet fluidicly independent of the first inlet connection; a piglauncher coupled to the inlet valve, the pig launcher adapted to launcha pig into the tubing coil through the inlet valve; a first outletconnection coupled to the outlet and adapted to allow the heated fluidto exit therethrough; an outlet valve coupled to the outlet fluidiclyindependent of the first outlet connection; and a pig receiver coupledto the outlet valve, the pig receiver adapted to receive the pig fromthe tubing coil through the outlet valve, the method comprising:maintaining operation of the system by continuing to supply the fluidthrough the first inlet connection into the tubing coil; opening theinlet valve; launching the pig into a tubing pass of the tubing coilthrough the inlet valve and into a flow path of the fluid; descalingtubing surfaces of the tubing pass while continuing to generate theheated fluid in the tubing pass; opening the outlet valve; ejecting thepig through the outlet valve into the pig receiver; and flowing theheated fluid generated upstream and downstream of the pig in the tubingpass through the outlet independent of the outlet valve.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a representative schematic diagram of a fire heater forheating hydrocarbon in a tubing coil.

FIG. 2 is a representative schematic diagram of an OTHRSG system with atubing coil.

FIG. 3 is a representative schematic diagram of an OTSG system.

FIG. 4 is a schematic perspective view of an OTSG facility forextraction of hydrocarbon from oil sands.

FIG. 5 is a schematic cross sectional side view of the OTSG unitproducing steam for extraction of hydrocarbon from the oil sands.

FIG. 6 is a side schematic view of an OTSG unit adapted to be operatedonline.

FIG. 7 is a top schematic view of the OTSG unit adapted to be operatedonline.

FIG. 8 is a schematic view of an exemplary tubing coil having multiplepasses.

FIG. 9 is a schematic view of an exemplary tubing coil having a singlepass.

FIG. 10 is a schematic view of an exemplary tubing coil having multiplepasses with valving and related connections adapted to allow onlineoperation of the OTSG system.

FIG. 11 is a schematic view of an exemplary tubing coil having a singlepass with valving and related connections adapted to allow onlineoperation of the OTSG system.

DETAILED DESCRIPTION

The Figures described above and the written description of specificstructures and functions below are not presented to limit the scope ofwhat Applicant has invented or the scope of the appended claims. Rather,the Figures and written description are provided to teach any personskilled in the art how to make and use the inventions for which patentprotection is sought. Those skilled in the art will appreciate that notall features of a commercial embodiment of the inventions are describedor shown for the sake of clarity and understanding. Persons of skill inthis art will also appreciate that the development of an actualcommercial embodiment incorporating aspects of the present inventionswill require numerous implementation-specific decisions to achieve thedeveloper's ultimate goal for the commercial embodiment. Suchimplementation-specific decisions may include, and likely are notlimited to, compliance with system-related, business-related,government-related and other constraints, which may vary by specificimplementation, location, and from time to time. While a developer'sefforts might be complex and time-consuming in an absolute sense, suchefforts would be, nevertheless, a routine undertaking for those ofordinary skill in this art having benefit of this disclosure. It must beunderstood that the inventions disclosed and taught herein aresusceptible to numerous and various modifications and alternative forms.The use of a singular term, such as, but not limited to, “a,” is notintended as limiting of the number of items. Also, the use of relationalterms, such as, but not limited to, “top,” “bottom,” “left,” “right,”“upper,” “lower,” “down,” “up,” “side,” and the like are used in thewritten description for clarity in specific reference to the Figures andare not intended to limit the scope of the invention or the appendedclaims. Where appropriate, some elements have been labeled with analphabetic character after a number to reference a specific member ofthe numbered element to aid in describing the structures in relation tothe Figures, but is not limiting in the claims unless specificallystated. When referring generally to such members, the number without theletter is used. Further, such designations do not limit the number ofmembers that can be used for that function.

The disclosure provides a heat transfer system having a tubing coil forheating fluid flowing therein, where the tubing coil can be pigged(descaled) while operationally online, instead of offline. The onlinesystem uses an assembly of valves and associated equipment to connect toa pig launcher and pig receiver while the system is online. A valveopens and the pig launches into the flow stream under pressure throughthe valve and travels along the tube with the fluid. The systemcontinues to produce heated fluid with the pig in the flow path. A pigreceiver receives the pig after the pigging, and then is isolated fromthe flow path of the heated fluid by another valve. The pig launcher,pig receiver, and pig are removed, and this process is repeated for anyother passes in the tubing coil.

As discussed above, heat transfer systems having tubing coils are usedin a number of applications. For the purposes of illustration, a heattransfer system will be described in terms of an OTHRSG system, andparticularly, an OTSG system. However, it is understood that theexamples herein are non-limiting, as the inventive concept and technicalsolution can be applied to other heat transfer systems having a tubingcoil for heating a fluid disposed therein. Thus, for example, while theheat source can be described as a burner that heats from fuelcombustion, as is generally used in an OTSG system, the heat source canalso include a turbine exhaust, a turbine exhaust coupled to a burner,electrical heating through resistive heating or induction heating,combinations thereof, and any other type of heating that can provideheat to a tubing coil for fluid therein. Similarly, while the fluid isdescribed in terms of feedwater and the heated fluid as steam, as isgenerally used in an OTSG system, the fluid can also include anyflowable substance that can be flowed in a tubing coil, includingwithout limitation hydrocarbons and other organic fluids, and otherflowable substances. Thus, while the OTSG is described in some detailrelevant to the inventive concepts, the exemplary components describedherein should be understood to encompass similar functional componentsin other heat transfer systems. For example, the heat source in thefollowing figures, shown as a burner, should be understood to alsoinclude other known types of heat sources, such as, but not limited to,the types of heat sources in the above list and shown as a block diagramin FIG. 5 above.

FIG. 6 is a side schematic view of an OTSG unit adapted to be operatedonline. FIG. 7 is a top schematic view of the OTSG unit adapted to beoperated online. FIG. 8 is a schematic view of an exemplary tubing coilhaving multiple passes. FIG. 9 is a schematic view of an exemplarytubing coil having a single pass. The figures will be described inconjunction with each other.

A heat transfer system, such as an OTSG system, 2 includes an OTSG unit8 generally described above with additional valving and other associatedequipment adapted to allow the OTSG unit to operate online whilepigging. A heat source 10, such as a burner, produces heat that isdirected into the OTSG unit heating chamber 15 that generally includes aheated fluid zone, such as a steam generation zone 14, and a fluidpreheat zone 12, such as for incoming feedwater. A tubing coil 16 isdisposed in one or more portions of the chamber 15. The tubing coil 16can include multiple tubing passes, such as tubing passes 17A, 17B, 17C,illustrated in FIG. 8, or a single tubing pass 17, illustrated in FIG.9, generally referenced as tubing pass 17. Each tubing pass 17 generallyincludes an accessible inlet 18 and outlet 20 with an inlet valve andoutlet valve coupled thereto, described in more detail in reference toFIGS. 10 and 11 below.

FIG. 10 is a schematic view of an exemplary tubing coil having multiplepasses with valving and associated equipment adapted to allow onlineoperation of the OTSG system. The chamber 15 contains a majority of thetubing coil 16 that is used to heat the fluid, such as feedwater, into aheated fluid, such as principally steam. The tubing coil generallyincludes one or more tubing passes 17, such as tubing passes 17A, 17B.This portion of the OTSG system is prone to developing the scale on thetube walls of the tubing passes and need periodic descaling.

The portion of the online OTSG system 8 shown in FIG. 10 includesvalving and associated equipment arranged and coupled to the inlet 18and the outlet 20 of the tubing coil 16 to allow the online OTSG systemto continue to operate while pigging. For example, the tubing pass 17Aincludes an inlet 18 is fluidicly coupled to an inlet connection 46 forthe supply of fluid, such as the feedwater, into the tubing pass.However, in the exemplary illustrated online OTSG system, the tubingpass 17A, and more generally the tubing coil 16, is also fluidiclycoupled independent of the first inlet connection to a second inletconnection 40 for coupling to a removable pig launcher 36, known in theart. The connection 40 is coupled to an inlet valve 42. The valve 42 iscoupled to another inlet connection 44. The connection 44 can be coupledduring operation of the OTSG system to the removable pig launcher 36.Thus, the connection 46 for the feedwater and the connection 40 for thepigging form two distinct points of access into the inlet 18 of thetubing coil 16. One or more of the pig launcher 36, valve 42, andconnections 40, 44 can be longitudinally aligned with a longitudinalaxis 60 of the tubing pass 17A at the inlet 18, and more generally thatportion of the tubing coil adjacent the connection 40, to facilitate thepig 58 being injected into the flow path of the tubing pass 17. In atleast one embodiment, the inlet connection 46 for the supply offeedwater into the tubing pass 17A will be nonaligned with thelongitudinal axis. The connections can be a flange, threaded connection,quick disconnect, or other means of coupling two elements together.Further, the connections can be separate or integral with anotherelement, such as a valve or spool having a connection on each end.

Similarly, the tubing pass 17A includes an outlet 20 fluidicly coupledto an outlet connection 48 for allowing the steam and any remainingheated feedwater to exit from the tubing pass. In the exemplaryillustrated online OTSG system, the tubing pass 17A, and more generallythe tubing coil 16, is also fluidicly coupled independent of the firstoutlet connection 48 to a second outlet connection 50 for coupling to apig receiver 38, known in the art. The connection 50 is coupled to anoutlet valve 52. The valve 52 is coupled to another outlet connection54. The connection 54 can be coupled during operation of the OTSG systemto the pig receiver 38. Thus, the connection 48 and the connection 50form two distinct points of exit from the outlet 20 of the tubing coil16. One or more of the pig receiver 38, valve 52, and connections 50, 54can be longitudinally aligned with a longitudinal axis 60 of the tubingpass 17A at the outlet 20, and more generally that portion of the tubingcoil adjacent the connection 50, to facilitate the pig being ejectedfrom the tubing pass and received into the pig receiver. In at least oneembodiment, the outlet connection 48 for the exit of steam from thetubing pass 17A will be nonaligned with the longitudinal axis. Anotherconnection 56 can be used as an additional access point to the tubingpass.

Each tubing pass can have an inlet valve and outlet valve coupledthereto so that the pig launcher and pig retriever can be coupled to thevalves while the OTSG system is online. Thus, the OTSG system 8 canremain online producing the heated fluid, such as the steam, during setup and assembly operations of the pig launcher 36 and pig receiver 38 inpreparation for a pigging operation to the tubing pass 17A. When theequipment is assembled and the pigging is about to be initiated, thevalve 42 can be opened to expose the pig launcher 36 and a pig 58 in thepig launcher to the inlet 18 of the tubing pass 17A. Similarly, thevalve 52 can be opened to expose the pig receiver 38 to the outlet ofthe tubing pass 17A.

The pig 58 is launched into the flow path of the feedwater/steam in theinlet 18. The launch can be actuated by higher pressure water or theforces on the pig into the flow path. The pig 58 travels along thetubing pass 17A to descale the tubular internal surfaces with thefeedwater pressure pushing the pig. The OTSG system is continuing toheat the tubing pass and produce steam downstream and upstream of thepig 58 in the normal course of operation. As the pig 58 ends the travelin the tubing pass 17A, the pig enters a portion of the tubing pass thatis aligned with the valve 52 and pig receiver 52. The mass of the pig 58along the flow path provides inertia to the pig to continue generallystraight through the valve 52 and into the pig receiver 38. However, thesteam in the tubing pass 17A exits the outlet 20 to continue to providesteam to the underground oil sands for production thereof. The valves42, 52 can be closed to isolate the pig launcher 36, pig receiver 38,and pig 58 in the pig receiver 38 from the flow path of the feedwaterand steam through the tubing pass 17A.

For tubing coils having multiple tubing passes, generally each tubingpass has an inlet, an outlet, an inlet valve coupled to the inlet, andan outlet valve coupled to the outlet. The pig launcher 36, pig receiver38, and pig 58 can be removed from the valves on the tubing pass 17A,and assembled in similar manner to valves on the tubing pass 17B forpigging the tubing pass 17B, and so forth until all tubing passes forthe OTSG unit are descaled.

Thus, the OTSG unit can remain online with all tubing passes operatingat full or substantially full load producing steam at significantly lessexpense to the overall system in maintaining operational throughput.

FIG. 11 is a schematic view of an exemplary tubing coil having a singlepass with valving and related connections adapted to allow onlineoperation of the OTSG system. In a similar fashion as described abovefor FIG. 10, the online OTSG system can be pigged without requiring theOTSG system to stop operation in an offline mode. The valving andconnections are mounted with the tubing coil to allow the pig launcher36 and pig receiver 38 to be connected to the tubing coil 16 having atubing pass 17 while the tubing coil is operational. The valve 42 can beopened and the pig 58 injected into the flow path of the feedwaterthrough the tubing pass 17 and is energized by the feedwater behind thepig to push the pig through the internal portions of the tubing pass 17while steam is generated through the pass. The pig receiver 38 receivesthe pig 58 through an open valve 52, and the steam exits the tubing coil16. The valves 42 and 52 can be closed to isolate the pig launcher 36and pig receiver 38 from the flow path through the tubing coil and thepig launcher and pig receiver disconnected to be used on another tubingpass or tubing coil of another OTSG unit.

Some of the potential advantages of the online OTSG system include:

-   -   reduced capital expenditures and operational expenditures, at        least in part, due to a reduced need of having extra OTSG units        to operate while an OTSG unit is placed offline for pigging;    -   potentially reduced footprint without a need for an extra OTSG        unit to maintain steam production while an OTSG unit is offline;        potentially more flexibility in design without the extra OTSG        unit as restraints on the design, placement, piping, controls,        and other factors associated with an additional unit;    -   increased steam production for existing systems having extra        OTSG units by having all OTSG units online without having to be        offline for pigging; and    -   potentially reduced maintenance, including labor and materials,        with the long term impact of additional thermal stresses on        shutting down and restarting OTSG units.

Other and further embodiments utilizing one or more aspects of theinvention described above can be devised without departing from thespirit of the invention. For example, the exemplary heat transfer systemcan be used in other environments besides production from oil sands.Further, the heat transfer system can be used for different types offluids including hydrocarbons and other organic fluids, including gases.Thus, the invention applies to any heat transfer system having a tubingcoil used for any application. Further, different connections andequipment can be used for a variety of connections and valves for theinvention and the embodiments of connections and valves are exemplarywithout limitation. Other variations in the system are possible.

Further, the various methods and embodiments described herein can beincluded in combination with each other to produce variations of thedisclosed methods and embodiments. Discussion of singular elements caninclude plural elements and vice-versa. References to at least one itemfollowed by a reference to the item may include one or more items. Also,various aspects of the embodiments could be used in conjunction witheach other to accomplish the understood goals of the disclosure. Unlessthe context requires otherwise, the word “comprise” or variations suchas “comprises” or “comprising,” should be understood to imply theinclusion of at least the stated element or step or group of elements orsteps or equivalents thereof, and not the exclusion of a greaternumerical quantity or any other element or step or group of elements orsteps or equivalents thereof. The device or system may be used in anumber of directions and orientations. The term “coupled,” “coupling,”“coupler,” and like terms are used broadly herein and may include anymethod or device for securing, binding, bonding, fastening, attaching,joining, inserting therein, forming thereon or therein, communicating,or otherwise associating, for example, mechanically, magnetically,electrically, chemically, operably, directly or indirectly withintermediate elements, one or more pieces of members together and mayfurther include without limitation integrally forming one functionalmember with another in a unitary fashion. The coupling may occur in anydirection, including rotationally.

The order of steps can occur in a variety of sequences unless otherwisespecifically limited. The various steps described herein can be combinedwith other steps, interlineated with the stated steps, and/or split intomultiple steps. Similarly, elements have been described functionally andcan be embodied as separate components or can be combined intocomponents having multiple functions.

The invention has been described in the context of preferred and otherembodiments and not every embodiment of the invention has beendescribed. Apparent modifications and alterations to the describedembodiments are available to those of ordinary skill in the art giventhe disclosure contained herein. The disclosed and undisclosedembodiments are not intended to limit or restrict the scope orapplicability of the invention conceived of by the Applicant, butrather, in conformity with the patent laws, Applicant intends to protectfully all such modifications and improvements that come within the scopeor range of equivalent of the following claims.

1. A heat transfer system, comprising: a heat source coupled to achamber having a tubing coil disposed therein, the heat source adaptedto heat at least a portion of a fluid in the tubing coil into a heatedfluid by providing heat to the tubing coil, the tubing coil having aninlet and an outlet, the inlet adapted to receive the fluid for flowingthrough a flow path in the tubing coil and the outlet adapted to allowthe heated fluid to exit the tubing coil; a first inlet connectioncoupled to the inlet for coupling with a supply line to supply the fluidinto the tubing coil; a second inlet connection coupled to the inlet andfluidicly independent of the first inlet connection; an inlet valvecoupled to the second inlet connection; a third inlet connection coupledto the inlet valve; a pig launcher coupled to the third inletconnection, the pig launcher adapted to launch a pig into the tubingcoil through the inlet valve; a first outlet connection coupled to theoutlet and adapted to allow the heated fluid to exit therethrough; asecond outlet connection coupled to the outlet and fluidicly independentof the first outlet connection; an outlet valve coupled to the secondoutlet connection; a third outlet connection coupled to the outletvalve; and a pig receiver coupled to the third outlet connection, thepig receiver adapted to receive the pig from the tubing coil through theoutlet valve.
 2. The system of claim 1, wherein the heat transfer systemcomprises a steam generator, the fluid in the tubing coil comprisesfeedwater, and the heated fluid comprises steam.
 3. The system of claims2, wherein the steam generator comprises a once-through steam generator,and the heat source comprises a burner.
 4. The system of claim 2,wherein the steam generator comprises a once through heat recovery steamgenerator, and the heat source comprises a gas turbine, a burner, or acombination thereof.
 5. The system of claim 1, wherein the fluidcomprises feedwater, the heated fluid comprises steam, and furthercomprising; a steam pipeline coupled to the outlet of the tubing coiland disposed in a geologic stratum having hydrocarbons, the steampipeline having an injection portion with openings to allow the steam tobe injected into the geologic stratum; a collection pipeline disposed inthe geologic stratum and having a collection portion with openings toallow heated hydrocarbons from the steam to flow into the collectionpipeline; and a processor adapted to process the heated hydrocarbonsafter collection.
 6. The system of claim 1, wherein one or more of thepig launcher, inlet valve, and second inlet connection and third inletconnection are longitudinally aligned with a longitudinal axis of thetubing coil adjacent the inlet.
 7. The system of claim 6, wherein thefirst inlet connection is nonaligned with the longitudinal axis of thetubing coil adjacent the inlet.
 8. The system of claim 1, wherein one ormore of the pig receiver, outlet valve, and second outlet connection andthird outlet connection are longitudinally aligned with a longitudinalaxis of the tubing coil adjacent the outlet.
 9. The system of claim 8,wherein the first outlet connection is nonaligned with the longitudinalaxis of the tubing coil adjacent the outlet.
 10. The system of claim 1,wherein the tubing coil comprises multiple tubing passes, and wherein atleast two of the tubing passes each have an inlet and an outlet and aninlet valve coupled to the inlet and an outlet valve coupled to theoutlet for coupling each of the at least two tubing passes to the piglauncher and the pig receiver.
 11. A method of pigging a heat transfersystem, the system having a heat source coupled to a chamber having atubing coil disposed therein, the tubing coil having one or more tubingpasses, the heat source adapted to heat at least a portion of the fluidin the tubing coil into a heated fluid by providing heat to the tubingcoil, the tubing coil having an inlet and an outlet, the inlet adaptedto receive the fluid for flowing through a flow path in the tubing coil,and the outlet adapted to allow the heated fluid to exit the tubingcoil, the heat transfer system further having: a first inlet connectioncoupled to the inlet for coupling with a supply line to supply the fluidinto the tubing coil; an inlet valve coupled to the inlet fluidiclyindependent of the first inlet connection; a pig launcher coupled to theinlet valve, the pig launcher adapted to launch a pig into the tubingcoil through the inlet valve; a first outlet connection coupled to theoutlet and adapted to allow the heated fluid to exit therethrough; anoutlet valve coupled to the outlet fluidicly independent of the firstoutlet connection; and a pig receiver coupled to the outlet valve, thepig receiver adapted to receive the pig from the tubing coil through theoutlet valve, the method comprising: maintaining operation of the heattransfer system by continuing to supply fluid through the first inletconnection into the tubing coil; opening the inlet valve; launching thepig into a tubing pass of the tubing coil through the inlet valve andinto a flow path of the fluid; descaling tubing surfaces of the tubingpass while continuing to generate the heated fluid in the tubing pass;opening the outlet valve; ejecting the pig through the outlet valve intothe pig receiver; and flowing the heated fluid generated upstream anddownstream of the pig in the tubing pass through the outlet independentof the outlet valve.
 12. The method of claim 11, further comprisingclosing the inlet valve and the outlet valve and continuing to flow thefluid into the inlet and the heated fluid out of the outlet.
 13. Themethod of claim 11, wherein the tubing coil comprises multiple tubingpasses, and wherein at least two of the tubing passes each have an inletand an outlet and an inlet valve coupled to the inlet and an outletvalve coupled to the outlet, and further comprising removing the piglauncher and the pig receiver from a first tubing pass and assemblingthe pig launcher and pig receiver to an inlet valve and an outlet valveon a second tubing pass.
 14. The method of claim 13, further comprisingpigging the second tubing pass while maintaining operation of the secondtubing pass.
 15. The method of claim 11, wherein the fluid comprisesfeedwater, the heated fluid comprises steam, and the outlet is coupledto a steam pipeline disposed in a geologic stratum containinghydrocarbons, and further comprising injecting the steam through thesteam pipeline into the geologic stratum to heat the hydrocarbons andcollecting at least a portion of the heated hydrocarbon into acollection pipeline.
 16. The method of claim 11, wherein the piglauncher is longitudinally aligned with a longitudinal axis of thetubing coil adjacent the inlet, and further comprising launching the pigfrom the pig launcher in alignment with the longitudinal axis of thetubing coil.
 17. The method of claim 11, wherein the pig receiver islongitudinally aligned with a longitudinal axis of the tubing coiladjacent the outlet, and further comprising receiving the pig into thepig receiver in alignment with the longitudinal axis of the tubing coil.